As it attempted to replace all the top skill-position players on offense from last season's team, BYU figured to take a small step backward.

The Cougars instead have fallen off a cliff.

The program that won at least 10 games in each of the past four seasons is off to its worst start since 1973. BYU (1-4) has lost four in a row -- and each by at least two touchdowns -- for the first time since 1993. This isn't exactly the type of season BYU needed as it prepares for its move to independent status.

BYU coach Bronco Mendenhall responded to the adversity by firing defensive coordinator Jaime Hill and announcing that he would run the defense. Mendenhall had run the defense each of his first three seasons as coach before handing those responsibilities to Hill in 2008.

Hill told the media afterward that he was being made a scapegoat for BYU's poor start. Mendenhall said it was a move he had to make.

"I've done what I think is right," Mendenhall said. "I bear complete responsibility for the decision. When and how it will affect the outcome on Saturday, I certainly don't know. But I know that both the players and coaching staff are anxious for my involvement, and I'm excited to do that."

Mendenhall said he believes he needs to play a bigger role on the team to help turn around the problems that led to the Cougars' poor start.

BYU clearly doesn't have as much firepower as it did last season. Former BYU quarterback Max Hall now is with the Arizona Cardinals. Dennis Pitta led all tight ends in receiving yards per game last season, while Harvey Unga led the Mountain West Conference in rushing.

But the Cougars didn't merely lose a bunch of talented players in the offseason. They also seemed to lose their identity. Mendenhall needs the Cougars to recapture it.

"My main goal is to improve and uncover the heart and soul of this particular team and have them play with more grit, determination, resilience and toughness," Mendenhall said. "This isn't really a scheme issue or a strategy issue. This is [about] capturing hearts and minds and inspiring."

While Hill took the fall, there's plenty of blame to go around. The Cougars are 101st in the nation in total defense, but they also are 114th in scoring. After beating Washington 23-17 in the season opener, the Cougars haven't scored more than 16 points in any of their past four games.

BYU opened the season with a two-quarterback system that didn't allow either Riley Nelson or Jake Heaps to establish a rhythm. A season-ending injury to Nelson eventually forced the Cougars to hand over the offense to Heaps, a true freshman.

Because of its inexperience on offense, BYU needed to lean heavily on its defense. But that defense has struggled because of a series of injuries, most notably knee problems that knocked nose tackle Romney Fuga out for the season and linebacker Jordan Pendleton for two to six weeks. BYU could be missing as many as five defensive starters for Saturday's game with San Diego State.

All those setbacks have left BYU with the poorest run defense in the nation, so it's hard to imagine the Cougars slowing down MWC rushing leader Ronnie Hillman of San Diego State this week.

"I think that's a little bit skewed," San Diego State coach Brady Hoke said of BYU's last-place status in run defense. "When you've played Nevada and you've played Air Force -- I think they're both in the top five or six in the country [in rushing] -- I think that skews those statistics. I don't think that's a great barometer."

It doesn't get any easier for BYU. Next week, the Cougars go on the road to face TCU, which has the nation's seventh-ranked rushing offense. BYU is staring at the realistic possibility of a 1-6 start.

Mendenhall looks forward to the challenge.

"I've learned more the past four weeks than I think I've learned in the previous five years combined," Mendenhall said.

He could get an even bigger education the next couple of weeks.

Best matchup: Iowa State rush offense vs. Utah rush defense. Iowa State is coming off a 52-38 victory over Texas Tech in which Alexander Robinson and Shontrelle Johnson each rushed for more than 100 yards. The Cyclones ran for 251 yards on 50 carries against the Red Raiders. Iowa State would love to establish that kind of rushing attack Saturday against Utah, but the Utes rank 11th in the nation in rush defense and are allowing just 2.4 yards per carry. Iowa State almost certainly won't have two 100-yard rushers against Utah, but the Cyclones must run the ball somewhat effectively to have a chance of winning.

Player on the spot: New Mexico QB B.R. Holbrook. Saturday's game at New Mexico State represents New Mexico's best chance to avoid a winless season. It also marks the potential return of Holbrook, who sat out the Lobos' past three games to recover from exploratory arthroscopic surgery on his left knee. Holbrook has returned to practice, though he hasn't officially been declared the starter for Saturday's game. Holbrook's return could boost an offense that ranks 117th in the nation in scoring and 118th in yards per game. If they're at full strength, the winless Lobos have a legitimate shot against New Mexico State, which has lost each of its four games by an average margin of 34.3 points. New Mexico has lost each of its five games by an average margin of 40.4 points. If Holbrook isn't ready to go, our player on the spot becomes true freshman QB Tarean Austin, who has a sprained ankle but should be available this week.

Numbers game: There still is some good news for BYU amid this dreadful season. All of BYU's setbacks during this four-game losing streak have been one-sided enough that the Cougars still own a 12-game winning streak in games decided by eight or fewer points. No other FBS team has won that many consecutive one-possession games.

What they're saying

"I told [TCU coach] Gary [Patterson] after the game that we could have played until midnight and we wouldn't have scored." -- Colorado State coach Steve Fairchild, after a 27-0 loss to TCU. The game started at noon local time

"Me, as a player, all I can do is play. I'll let others worry about style points or how many points we put up on them. All I can do is just my part." -- TCU WR Jimmy Young, to the Fort Worth Star-Telegram

"I haven't seen enough football to say. I can worry about just my program and I can tell you I haven't been happy with the outcome of our games, but I also have seen some things in our program that lead me to believe we're headed in the right direction." -- New Mexico coach Mike Locksley, in response to a question about whether Saturday's game with New Mexico State matched two of the poorest FBS teams in the country

"If we're talking about how much stuffing was in the turkey and the quality of the pumpkin pie, that's the time of year for that." -- Air Force coach Troy Calhoun, talking to The (Colorado Springs) Gazette about the appropriate time to worry about rankings. Air Force entered The Associated Press poll at No. 25 this week, marking the first time the Falcons have been ranked since 2003

"It can be very dangerous. Coach Hoke has said that they're a wounded bear. They're ready to come in and attack us and do whatever it takes to get a victory. It's definitely a dangerous game." -- San Diego State WR Vincent Brown, about facing a BYU team on a four-game losing streak

Etc.: New Mexico's Myles Daughtry became just the second freshman in MWC history to score on a kickoff return when he delivered a 100-yarder in a 38-20 loss to UTEP. The only other freshman to accomplish that feat was Colorado State's Dexter Wynn against San Diego State in 2000. … Wyoming is about to become the only team in the nation to face three top-five teams in the first six weeks of the season. Wyoming faced Texas on Sept. 11 and Boise State on Sept. 18. The Cowboys play at No. 5 TCU this week. The Texas and Boise State games marked the first time Wyoming had faced top-five teams in consecutive weeks. … Air Force has outscored opponents 54-0 in the fourth quarter this season. Oregon is the only other FBS team that hasn't allowed a fourth-quarter point. … TCU has allowed seven touchdowns in its past six home games. The Horned Frogs have outscored opponents 298-61 in those six games. TCU hasn't lost a Saturday home game since falling 35-31 to Tulane in its 2004 season finale. … TCU QB Andy Dalton set a school record Saturday by throwing his 50th career touchdown pass. … UNLV's game with West Virginia represents the first time the Rebels have played in the Eastern time zone since a 2004 game at Tennessee. The Rebels haven't traveled this far east since a 1972 game at Miami. … UNLV CB Will Chandler has four interceptions and two fumble recoveries to lead the nation with six takeaways. … Colorado State RB Raymond Carter has a sprained knee that likely will prevent him from playing Saturday at Air Force. Carter is the Rams' leading rusher with 143 yards on 44 carries. … Utah has scored on a punt return in three consecutive games. … San Diego State and TCU are two of only six teams to rank in the top 25 in scoring offense and defense and total offense and defense. The others are Alabama, Boise State, Nebraska and Ohio State.